1. Field of the Invention
The present invention relates to a digital camera, and, more particularly, to a camera capable of shooting a still image at a shutter timing determined by the camera.
2. Description of the Related Art
In the recent camera market, improvements on image pickup sensors such as a CCD (Charge Coupled Device) can ensure fast reading of a large amount of image signals in a short period of time. Conventional large-pixel image pickup devices of, for example, 5 million pixels or greater have a reading speed of several tens of milliseconds. However, some image pickup devices that can read image signals at 60 fps (frame per second) have been proposed recently.
Accordingly, there are many digital cameras designed for shooting still images merchandised which can also shoot movie images too. Also on the market are a lot of movie cameras for shooting movie images which can take an improved image quality of still images.
For example, Japanese Patent Application Laid-Open No. 2004-64467 describes a camera capable of acquiring a smooth movie image even if a still image is shot with an electronic flash fired during shooting of the movie image. This camera drives an image pickup at a frame rate double of the frame rate necessary to capture a movie image. In a case of shooting a still image, the camera reads a frame for recording a still image between frames for recording a movie image. The electronic flash is fired during the light reception period for the still-image recording frame.
Japanese Patent Application Laid-Open No. 2005-57378 describes an imaging device capable of shooting a high-quality still image as well as shooting a movie image at a high frame rate. This imaging device records image data output from an image pickup device driven in thin reading mode, as a movie image, and records image data output from the image pickup device driven in full-pixel reading mode, as a still image.
Recently, various fast CMOS (Complementary Metal Oxide Semiconductor) sensors and circuits which are designed as compatible therewith to ensure fast acquisition of pixel signals have been realized. So have been proposed cameras for recording a movie image and a still image using such a fast-reading image pickup device.